Evaluate the following integrals and choose the correct option: integral (1)/(sqrt(1-x2)) dx integral (1)/(1+x2) dx

The integral $\int \frac{1}{\sqrt{1-x^2}} dx$ is a standard integral.

$$\int \frac{1}{\sqrt{1-x^2}} dx = \sin^{-1}x + C$$

Comparing this with the given options, option C matches.

The final answer is $\boxed{\text{C}}$

The integral $\int \frac{1}{1+x^2} dx$ is a standard integral.

$$\int \frac{1}{1+x^2} dx = \tan^{-1}x + C$$